1. Field of the Invention
The present invention relates generally to a golf club head made of a metallic material, and in particular, to a golf club head of the foregoing type durable against shock upon hitting a golf ball and capable of driving a golf ball further.
2. Description of the Related Art
So-called iron club head is generally made of a metallic material such as soft steel, stainless steel or the like so that hosel, sole and face portions thereof are integrated with each other.
As is well known, each of golf club heads of the foregoing type is made with a different configuration and a different weight corresponding to a given club head number. However, because of mass of metallic material, the golf club head lacks elasticity. Especially, when a face portion of the golf club head, i.e., a most important portion of the same for hitting a golf ball has few elasticity, it exhibits a small value of repulsive coefficient. In addition, with the iron club head, a golf player can not enjoy soft hit feeling attainable when he hits a golf ball with a wood club.
To assure that a golf player can enjoy soft hit feeling also with an iron club head, a proposal is already made with respect to a golf club head as disclosed in Japanese Utility Model Publication No. 35-31514 wherein a face plate molded of a synthetic resin is secured to a face portion of the golf club head by tightening screws.
As shown in FIG. 4, according to this prior invention, a face plate 9 molded of a synthetic resin and having a concave recess 7 formed on the rear surface side is detachably secured to a recessed part 5a of a face portion 3 of a main body 1 by tightening screws 11.
With this construction, since the face plate 9 has a reduced thickness in the hitting range attributable to the formation of the concave recess 7 on the rear surface side, and moreover, a gap 13 is formed between the concave recess 7 of the face plate 9 and a bottom surface 5a of the recessed part 5, it can be expected that a certain magnitude of repulsive force is generated by elastic deformation of the face plate 9.
It is certain that the repulsive force is generated to some extent with the face plate 9 having the concave recess 7 formed on the rear surface side in that way. However, there arises a problem that the strength of the face plate 9 is degraded due to reduction of the thickness of the face plate 9 in the hitting range. In addition, since the gap 13 is not formed in the hermetically closed state, the air remaining in the gap 13 does not exhibit a cushioning function for attenuating the stress appearing on the hitting surface of the face plate 9. Thus, there is a possibility that the face plate 7 is broken as the golf club head is repeatedly used for a long time.
Further, a proposal is made with respect to a wood club head as disclosed in Japanese Utility Model Laid-Open Publication NO. 49-50063 although this is not concerned with the iron club head. As shown in FIG. 5, according to this prior invention, the wood club head is constructed such that a tip 17 made of cemented tungsten carbide or titanium carbide is fitted into the central part of a hitting range on a face plate 15 molded of a synthetic resin of which rear surface is recessed, and the face plate 15 is then fitted into a recessed part 23 of a face portion 21 of a main body 19.
With this construction, it can be expected that a certain magnitude of repulsive force is generated by the face plate 15 attributable to the formation of the recessed part 23 on the rear surface side. However, there is a possibility that the face plate 15 is broken due to repeated shock imparted thereto in the same manner as the iron golf club shown in FIG. 4 as the wood club head is repeatedly used for a long time.